This invention relates to a catalytic reactor for bringing a gaseous starting material into contact with a solid catalyst to cause an exothermic conversion reaction and hence to obtain a gaseous reaction product.
It is conventional, in a catalytic reactor, to divide a catalyst bed into plural smaller beds and to interpose a heat exchanger between each two successive ones of the smaller catalyst beds, so that the temperature in each smaller catalyst bed can be maintained at the level most suitable for the desired reaction whereby to cause the reaction to proceed to the maximum extent. Among the vertical catalytic reactors known to date, there are those equipped individually with such smaller catalyst beds, each of which is constructed of gas-transmitting inner and outer cylinders which are closed at both upper and lower ends thereof. Each catalyst bed is annular in transverse cross-section and has a cylindrical external shape and allows the reaction gas to flow radially therethrough so that the pressure drop of the gas that is passed through the catalyst bed can be reduced.
Among the prior art catalytic reactors, the following recent publications are mentioned.
Japanese Patent Laid-Open No. 81129/1981
Japanese Patent Laid-Open No. 110328/1985
Japanese Patent Laid-Open No. 179131/1985
In the catalytic reactors of these publications, each heat exchanger is located, for example, in the open central space of an annular catalyst bed or in a space above or below the catalyst bed within a reactor vessel.
In the aforementioned prior art, the catalyst beds and heat exchangers are arranged rather simply within the space of a reaction vessel. Maintenance and running costs were, however, not fully taken into consideration. They have, inter alia, one or more of the following drawbacks.
(1) The catalytic reactors have complex internal structures and their manufacturing costs are high.
(2) It is troublesome and time-consuming to assemble and disassemble their heat exchangers. It is impossible to take out the heat exchangers until after the catalyst has been removed completely. Their maintenance is thus difficult to perform, leading to higher repair costs.
(3) The heat exchangers are designed in accordance with the quantities of heat to be generated in their corresponding catalyst beds. It is, however, very difficult to match the size of a heat exchanger, which is to be installed, with the size of its corresponding catalyst bed because the space provided for receiving the heat exchanger is limited.